題目描述

17. Letter Combinations of a Phone Number

代碼：

class Solution {string table[10] ={"","","abc","def","ghi","jkl","mno","pqrs","tuv","wxyz"};vector<string> res;
public:vector<string> letterCombinations(string digits) {int len = digits.size();if(len == 0)return res;string com;backtracking(0,digits,com);return res;}void backtracking(int start,string &digits,string &acom){if(start == digits.size()){res.push_back(acom);return;}string temp = table[(digits[start] - '0')];for(int i = 0;i < temp.size();i++){acom.push_back(temp[i]);backtracking(start+1,digits,acom);acom.pop_back();}}
};